Azoospermia is a clinical condition characterized by zero sperm count in the male semen. Approximately 2% of the general population is affected by this disorder. Azoospermia occurs when there is obstruction of the reproductive tract or due to inadequate production of spermatozoa (sperm cells).

Basically, sperm cells do not appear in the ejaculate with azoospermia. This condition is diagnosed by semen analysis. Many men diagnosed with azoospermia are surprised because they have no problems with libido, semen appearance, or sexual function.


What is the difference between azoospermia and aspermia?

Azoospermia is different from aspermia. With aspermia, there is a total absence of sperm, which is a much more rare disorder than azoospermia. With azoospermia, there is sperm produced, but it is not always present in the semen.


What are the causes of azoospermia?

There are two possible reasons for azoospermia. These include:


  • Obstructive azoospermia (sperm transport problems) – This is a blockages in the ducts responsible for transporting sperm from the testes (testicles) to the penis. Testicle and sperm production levels are usually normal for men with this condition. However, fructose is seen in the semen, as well as an alkaline pH. Along with these abnormal findings, semen volume remains normal. Obstruction is often related to an absent vas deferens or due to a seminal vesicle obstruction. Obstructive azoospermia accounts for 40% of all cases of azoospermia.
  • Non-obstructive azoospermia (sperm production problems) – With this form of azoospermia, the testicles do not produce any sperm. Also called testicular failure, the passageways are normal with this form of azoospermia. For men diagnosed with this disorder, it is possible for certain regions of the testes to produce sperm, but the levels are so low sperm is not detectable. With this type of disorder, biopsies must be performed. Around 60% of men with azoospermia have non-obstructive type.


Conditions that can cause azoospermia include:

  • Kallman syndrome (secondary testicular failure)
  • Klinefelter syndrome (primary testicular failure)
  • Y chromosome microdeletions
  • Abnormal chromosomes (karyotype)
  • Hyperprolactinemia
  • Varicocele
  • Cancer treatment (radiation, chemotherapy, surgery)
  • Unexplained gonadotropin deficiency
  • Hypothalamic/pituitary tumor
  • Testosterone supplements
  • Pituitary suppression by anabolic steroids, glucocorticoids, and alcohol
  • Sickle cell anemia
  • Severe illness (kidney or liver failure)
  • Epididymitis
  • Undescended testicles
  • Hemachromatosis
  • Sperm autoimmunity
  • Pesticide/toxin exposure (including hot tubs and baths)
  • Young syndrome
  • Vasectomy


What is sperm retrieval?

According to a recent study, sperm retrieval for assisted reproduction has a pregnancy success rate of around 40%. When extracted from the testes, pregnancy rates using in vitro fertilization and intracytoplasmic sperm injection increase to around 50%.

What is the treatment for azoospermia?

There are several treatment options for azoospermia. These are:


  • Blockage removal – This applies to the duct system. Blockages can be fixed using hormone medications as well as surgery. Surgical sperm removal is most often done when a blockage exists. Surgery involves endoscopic reconstruction.
  • Percutaneous sperm aspiration (PSA) – This involves aspirating sperm from the epididymis and injecting it into the female‚Äôs eggs. Excess sperm can be frozen for use in the future.
  • Testicular sperm extraction (TSE) – This involves retrieving sperm directly from a testicle. Sperm cell product occurs in the testes, and of those who undergo TSE, half have very few or no sperm. When viable sperm are found, the female’s eggs can be fertilized using intracytoplasmic sperm injection.



Schlegel PN (2004). Causes of azoospermia and their management. Reproductive Fertility Development, 16(5), 561-572.